The external surfaces of tall buildings require treatment from time to time for aesthetic and/or functional reasons. For example, it is desirable to clean the outside surfaces of the buildings' windows.
Several techniques are adopted to gain access to a building exterior for the purpose of effecting required treatments of the building. The majority of buildings do not feature external access ways surrounding each floor, which could be used by a worker to execute external cleaning of the building. In these cases, one normally relies on erecting scaffolding. Alternatively, some buildings use a small scaffold platform, which may be supported by a cable and is attached to an appropriate securing device on the roof of the building.
The disadvantages of these practices include the following. Firstly, there is a danger of the worker falling due to adverse weather conditions, or due to human error. Secondly, the worker is exposed to high concentrations of the materials being used to treat or clean the building. Thirdly, this work is labor intensive and repetitive and therefore as the worker tires, the job takes a longer time.
The background art contains several automated devices to try to overcome the aforementioned problems, such as U.S. Pat. No. 5,240,503, and U.S Pat. No. 5,707,455, which disclose systems for treating exterior surfaces of a building. These devices use a separate power supply for the driving source.
The background art includes devices that can be used for automated cleaning of building surfaces and machines that use suction. U.S. Pat. No. 5,487,440, U.S. Pat. No. 5,366,038, U.S. Pat. No. 3,958,652 and U.S. Pat. No. 4,095,378 disclose robots for performing a working operation on a surface, which use a series of vacuum cups to engage the surface to be traversed. However, these devices are all powered by through a specially provided power source.
The known devices for cleaning tall buildings suffer from the following disadvantages. Many of these devices are very heavy due to the presence of weights (used to stabilize the devices) and electrical motors. The devices that do not use suction are affected by the weather conditions. In conditions of strong wind, these devices are unable to stay in one position. None of the existing devices can move at the same time as cleaning. In addition, they cannot access angled surfaces on buildings, such as corners, and consequently cannot clean such surfaces.
There is therefore a need for a system and method, such as is disclosed in the present invention, to provide a solution to the aforementioned problems and to be more efficient and cost-effective than known automated cleaning devices.